Multibeam Folded Transmitarray Antenna for Massive MIMO Applications

This paper presents a novel multibeam fully-planar folded transmitarray antenna (FTA) for massive MIMO applications. The FTA is composed of a planar metasurface-based transmitarray, a planar reflectarray and five small planar identical feeders. Both transmitarray and reflectarray are able to twist the polarization of the incoming electromagnetic (EM) waves 90° while the transmitarray could also provide transmission compensation phase at the same time. A FTA example is designed and simulated. The results successfully demonstrate the multibeam functionality, with appropriate aperture efficiency and impedance bandwidth.